Retractile device



June 13, 1933. B. FREILE El AL RETRACTILE DEVICE Original Filed May 21 1950 .FHE/LE A. C. MAGRATH ATTOEW S UNI D STATES and can be attached tothe present standard.

Patented June 13, 1933 Bauer: FREILE, or BOGOTA, New JERSEY, Ann nivrnrrnc; MAGBATH, or BROOKLYN, M NEW YORK, nssrenons T BELL TELEPHONELABORATOBIES, mconronn'rnn or NEW YORK, N. Y., aconronA'rronfon NEWYQRK nn rnAcTILE nnvrcn This invention relates to retractile spring assemblies and particularly to those for the restoration of switches employed in telephone and other systems.

i f The objectsare to reduce the number of failures which have been encountered with It has been he custom inthe past to restore the shafts of automatic switches by means of coiled springs such as those used in clocks. Springs of this type have been found to have certain disadvantages. The friction offered by the convolutions of the spring as it is wound isan added load on the switch operating magnets. They are liable to lock in their 'tensionedcondition, thus failing to restore the shaft; theyare sub e ct to'brealring; and, moreover, the assemblies of which they are a part are costly to manufacture and maintain in adjustment.

i The presentinvention is an improvement over the devices of the prior art in that it enables the use of a helical type spring, which isbetter suited to fulfill the requirements changes. These results are securedby means of a spring assembly which in cludes an extension tube that fits over the end of the standardiswitch shaft and is secured thereto by means of the fastening device that attaches thestopfinger. The hub member, to which the stopgbracket is secured, fits loosely on over the extension tube. In the upper end of the extension tube a locking slot ofthe, bayonet-joint type is provided. The helical springfits on over the extension tube and hub member and has a loop in its lower end which attaches to aprojection on the bracket.

The upper end of the helical spring; is sef L curely attached. to a cap and a sleeve which slides on over theextension tube. The end of the wire, which forms the helical spring,

is so disposed as to pass diametricallyacross the sleeve suchthat it engages saidlocking slot to secure the spring to the extension tube. To adjust the tension of the spring, it is only i am filed may 21, 19t O,Seria1 No. 454,368. Renewed August 10, i932.

necessary to seize the cap member, disengage the spring from the locking slot, give itthe necessary number of turns, gage it'in said slot. H

Afeature of the invention is an assembly of thekind above described in which the various parts are held in their positions relative to'one another by means of opposing her and the other on a sleeve secured to said cap and disposed Within the helix or the spring and around the shaft. There is a PATENT OFFICE if and then reeni shoulders, one on the shank of the hub memnormal clearancebetween these shouldersto permit proper freedom of movement of the parts butnot sufficient toallow anypart to work outof place. s a s Although helicalsprings havelbeen pro,- posed for restoring switches, the assembly which applicants have invented is an im provement over these prior devices in that it greatly facilitates replacement and makes it possible to secure the correct adjustment Withthe leastamount of difiiculty andper mits more efficient use. ofthe motive power of the spring.

The invention is illustrated the accom panying drawing, inwhich Fig. 1 shows a portion of a two-movementstep-bystep selector switch including theretractile device for restoring the brush shaft to its normal position. Fig. 2 is an enlarged view ofthe retractile spring assembly showing the various elements partly disassembled. Fig. 3 is a detail of the assembly.

Inasmuch asfthe construction and opera? tion of selector switches of the type to which this invention is applicable are wellknown to thoseskilled in the art, it is not considered necessary to show the full details of such a switch. Reference,however, may be made to the patent to Keith et al No. 815,176, granted March 13,1906. I

Referring first to 1 ofthe,accom panying drawing, the brush shaft 1Qof ai switch of this kind carries a plurality of brushes 19, 20, and 21, which cooperate with rowscf contacts in a terminal bank (not shown) A set of vertical operating magnets 22fmounted on the switcliframe,,operate an armature 23, which in turn actuates the stepi ping pawl 24. Pawl 24 engages the vertical ratchet 28 to step the brush shaft vertically in a step-by-step manner. The shaft 1 is held in its vertical position by the holding dog 32. After the switch has been positioned in its vertical movement, the rotary magnets 25 are energized to operate the armature 26, which in turn actuates the rotary stepping pawl The pawl 27 engages the rotary ratchet 29 to rotate the shaft 1, which advances the associated brushes into engagement with the sets of terminals in the terminal bank. The shaft 1 is held in its rotary position by the holding dog 35, which engages the rotary ratchet 29. I r

During the vertical movement of the brush shaft, the retractile spring assembly, which is connected to the top of the shaft, moves bodily therewith. During the rotary movement of the shaft 1, the retractile spring 16 is tensioned so as to restore the shaft 1 in its rotary direction when the shaft is released. The release of the shaft is effected by energizing the release magnet 30 to disengage the holding dogs 32 and 35. The shaft releases first in its rotary direction and then in its vertical direction.

The spring assembly comprises an extensiontube 2 (shown in Fig. 2) which fits easily on over the end of the brush shaft 1. The tube 2 has a notch 5 cutin the lower end thereof which registers with a notch 4 in the shaftwhen the tube is adjusted to its correct position on the shaft. The tube is held to the shaft 1 by means ofa clevis 6 and a combined locking key and stop finger 8. \Vith the tube in place onthe shaft, the looking key 8 is passed through an opening in the clevis and into the slots 4 and 5. With the'parts in this position, the set screw 7 is tightened, thus fastening the tube 2 and the stop finger 8 securely to the shaft 1.,

The stop bracket 9 is equipped with a hub portion 10, which is securely attached thereto and has an opening of suflicient diameter to receive the extension tube 2. The stop bracket 9 also has an opening 12, which loosely receives the post 34-secured to the frame 33 of the switch. To assemble the stop bracket 9, it is passed on over the tube 2 until it encounters the upper surface of the levi 6L I The assembly also includes a spring unit comprising a sleeve 15 of sufficient diameter to admit the extension tube 2. The sleeve 15 is notched at its upper end to receive the end of the wire 18 that forms the helical rectractile spring 16. With the wire 18 passing diametrically across the sleeve 15 and resting in the notches thereof, a cap member 14 is fitted on to the end of the sleeve and, while in this position,secured thereto by turning over the upper edges of the sleeve. This process firmly secures the cap, sleeve, and spring together as a unit. To finally assemble the complete device, the cap and spring unit is passed on over the end of the extension tube 2 until the end of the wire 18 enters the bayonet joint slot 3 in the upper end of the tube 2. The free end of the spring 16 is fashioned to provide a hook 17, which engages a projecting piece 13 on stop finger 9. WVith the lower end of the retractile spring thus secured to the stop bracket 9, the. cap 14 may be given a number of turns to tension the retractile spring before dropping into the locking slot 3.

\Vhen the retractile elements are thus assembled, the shaft 1 is urged by the tension in the spring 16 until the stop'finger 8 engages a depending portion 11 of the stop bracket, thus defining the fully released position of the shaft. l vith the stop finger 8 pressing against the stop bracket 11, the forces of the spring are confined within the assembly. so that the stop bracket 9 offers no friction as it slides along the vertical post 3st when the shaft 1 is moved vertically. When, however, the shaft is rotated, the post 34 prevents the stop finger from participating in the rotary movement of theshaft, and thus the spring 16 is further tensioned. As soon as the holding dogs are removed as above noted, the tension in the spring rotates the shaft back to its normal rotary position where the stop finger 8 engages the depending portion 11 of the bracket 9. Thereupon, the shaft 1 restores to its normal vertical position. Shaft lis prevented from restore ing in. its vertical direction until it has completely restored inthe. rotary direction by means of afurther holding dog (not illustrated in the drawing). It will be seen from the drawing that a vertical. slot 36 is cut in the teeth of the ratchet 28. A stationary dog normally lies within this slot when the shaft is in its normal rotary position. As soon as a rotary step is taken, however, the dog passes underthe corresponding vertical tooth in the ratchet 28. This holds the shaft against release until it has restored to its normal rotary position regardless of the fact that the holding dog 32 may have been withdrawn.

With the elements of the spring assembly in their proper relative positions, there is a slight clearance between the lower edge of the sleeve 15 and the upper edge of the hub member 10. This is clearly seen in Fig. 3. The purpose of this clearance is to permit a certain amount of freedom of the relatively movable parts. The opposing edges, however, prevent these parts from becoming unduly displaced due to forces set up the tension of the retractile spring 16.

vVhat is claimed is:

1. In combination, a rotatable member having a locking slot in the end thereof, a non-rotatable member, a spring having a pluralityof turns surrounding said rotatthis member ma having one end seem-ea to said min-rotatablemember and the other d lied to saidrotatable meniber by enllk, sociated \vitlrsaid spring for rotatingit ela ti le to said shaft to enable it from saidslot, H l 7 a y 3 l 3. In combination, a rotatable shaft, a 3 nember securedto saidshaft having a recess in the end t h reof, anon-rotatable f member oc'iated with sid shaft, awnof suit able material fa ioned to give a spring in the rel-"m e1 1- d to said iron-rotatable member, ecurely attached, to the sai d wire "g atthe other end thereof} id cap a concentric opening,the latter end of w re spring beingso disposed as to pass diametrically ac oss the o 'iening in said cap and toengagc said recess to loclr said spring}; tothe shaft. a i, p 4. In combination,a movableswif U havingian sion piecewitlia locking 1' siirr shaf in he end hereof, ahub memberloosely onnding said extension piece, a bracket to which saidhubjis securely fiXed,a sleeve surrounding the end of said extension piece, ya {cap securely attached to said sleeve, and. a helical spring surrounding said hub: ineni-- ber and said sleeveandihaving one end secured to the hub and; the other end secured to, said cap and sleeve and also secured to said extension piece by engagement in saic recess, said hub member and sleeve presenting opposing shoulders to prevent undue disv placement of the abovementioned elements 5. In combination, a switch shafthaving an extension piece with a" locking slot in the end thereof, a brackethaving an opening through which said extension piece ,freely passes, a stationary member towhich said 1 bracket ispattached, a stop finger securely at- ,tached to said. switch shaft and engaging a portion of said bracketto limit the restoring movement of the switchshaft, a helical spring surrounding said shaft and having one end securedto said bracket and the other end engaging said lockingslot, and means attached to the latter end oftsaid spring to facilitate its disengagement from and reengagement with said slot for the purpose of adjusting the tension. V p 6; In combination, a rotatable shaft, a hollow extension member, one end of which 165 receives the end of said shaft, the other end er said I extensionmember having a recess therein, means for securely ffastening said extension member to said shaft,a non-rotatable member, a sleeve member surrounding said eX-tensionmember, and a, cylindrical spring surrounding said sleevemember and having one end secured to said non-rotatable 1nember and the other end secured to said sleeve member and to said extension member by a locking engagement with said recess 7 :iI-n combination, a shaft, an extension tube, one end of which receives the end of said shaft, the other end of said tubehaving lockifng slot therein, means for securely fastening the tube to saidshaft for movementtherewithya stop member associated with said shaft, and a helicalspring surrounding said tube and having one end ee cured to, said stop member-wand the other end secured to said extension tube by de tachable engagement with saidflocki ng slot. 8.111 combination, a shaft, a, hollow eXten sion member, one end of which receives the ,end of said shaft,a stop finger for limiting the movement said shaft, means for se- "curelly fasteningboth said stop finger and said extension member to said shaft, said GX- tension member liavii'iga recess formed in the end thereof, a stop member associated Withsaid shaft and arrangedto permit movelllflllt of the shaft with respect thereto, and a helical spring surrounding said extension inember and having one end secured tojsaid stopmember and theother end detachably engagedinsaidrecess;" 9, In combinationfa movableshaft having a notch formed therein, an extension tube, one end of which receives the end of said shaft, the other end of said tube having a lockingfslot therein, said extension xtube also havinga notch thereinya stop finger for limiting the movement of said shaft, means for fastening said step finger insaid notches to rigidly securesaid extension tube and stop finger to said shaft,a stop bracket coacting with i said stop finger, and a spring surroundingsaid extension tube andihaving one end attachedto said stop bracket andthe other end to said tube by engagement with said k s-s t a l M 1O.In comb ation,;a rotatable shaft, an extension tube, one end of which receives the end of saidshafhftheotherend of said tube havingya lockiiigrecess thereinfm eans for fastening said tube tosaid shaft, a nonl-ro- 1m ftatable stop braclret including a hub per tion surrounding said tube and permitting IHOV GiDEDt Offtl'LG tube therein, and a: cylin drical retractilespring disposed, about said tube andhavingone end secured to said stop bracket and the other end adjust-ably secured to saidextension tube by engagementpin said locking recess.

, 1Q- lneoinbiii'ation, a rotatable shafa' an the end of said shaft, the other end of said tube having a locking slot therein, means for securely attaching the tube to the shaft for rotation therein, a non-rotatable stop brackct having an opening through which said tube passes, a helical spring surrounding said tube and having one end secured to said bracket and the other end secured to said tube by engagement with said locking slot, and a cap attached to the latter end of sa d spring to enable its disengagement from said slot for adjustment.

12. The combination in an automatic switch of a rotatable shaft, an extension tube, one end of'which receives the end of said shaft, the other end of said tube having a locking recess therein, means for clamping said tube to said shaft for rotation therewith, a stop bracket having anopening at one end thereof within which said tube and shaft rotate, a stationary rod, said stop bracket having an opening in the other end thereof for slidable engagement with said rod, and a retractile spring surrounding said extension tube and having one end secured to said stop bracket and the other end adjustably secured to said extension tube by engagement with said locking slot.

13. In combination, a rotatable member having a locking recess therein, a second member, and a spring having a plurality of turns disposed about said rotatable member and having one end in engagement with sald second member and the other end secured to said rotatable member by engagement in said locking recess, said spring being readilydlsengaged from said recess to enable ad ustment.

1 1. In combination, a rotatable member having a receptable in one end thereof, a second member, and a helical retractile spring having one end connected to said second member and the other end attached to said rotatable member by engagement in said receptable, said spring being readily detached from said rotatable member to enable an adjustment of its tension.

15. In combination, a non-rotatable member, a helical retractile spring having one end attached to said member, and a rotatable member disposed within said spring and having its end fashioned to provide a detachable connection with the other end of said spring such that a slight rotary movement of said spring enables its'detachment from the rotatable member.

16. In combination, two members, one of which is rotatable relative to the other, and a helical retractile spring disposed about one of said members and having one end secured to one of said members and the other end engaged in locking recess in the end of the other one of said members, said spring being detachable from said recess to enable adjustment of its tension by a slight rotary movement.

17. In combination, a sleeve having a slot cut in one end thereof, a coiled retractile spring disposed about said sleeve and having one of its ends arranged in said slot, a cap fitting over the end of said sleeve and into said slot, said parts when thus assembled being secured as a unitary structure by over turning the slotted end of said sleeve, a nonrotatable member to which the free end of said spring is attached, and a rotatable member disposed within said sleeve and having a locking slot in the end thereof, said unitary structure bein detachably connected to the rotatable mem er by engagement of the firstmentioned end of said spring in said locking slot.

18. In combination, a cylindrical sleeve having slots cut in one end thereof, a retractile spring coiled about said sleeve with one of its ends arranged in said slots and passing across the open end of the sleeve, a cap fitting over the end of the sleeve end and into said slots, said sleeve, spring, and cap when thus assembled being clamped together as an integral spring structure by overturning the slotted end of saidsleeve, a rotatable member disposed within said sleeve and having a locking recess in the end thereof for detachable engagement by the clamped end of said spring, said recess being so shaped that a slight rotary movement of said cap permits the disengagement of said spring structure fromsaid rotatable member, and a relatively non-rotatable member to which the free end of said spring is connected.

In witness whereof, we hereunto subscribe our names this 19th day of May, 1930.

BRUCE FBEILE. ARTHUR C. MAGRATH. 

